Speed responsive control



SPEED RESPONSIVE CONTROL Filed July 27, 1929 4 Sheets-Sheet 1 by hisaffarlwys MMWM Aug. 11, 1931. Y w, T, TABB 1,818,826

` SPEED RESPONS IVE CONTROL Filed July 27. 1929 4 sheets-sheet 2 Warner7'.' Tabl,

by his aawzeys Aug. 11, 1931. w. T. TABB SPEED RESPONSIVE CONTROL FiledJuly 27, 1929 4 Sheets-Sheet 5A lNvENoR Warner T. Tabl,

Ms' czfarneys Y Aug. 11, 1931. w. T. TABB SPEED RESPONSIVE CONTROL FiiedJuly' 27. 192s 4 Sheets-Sheet 4 INVENTOR Warner T'. Tabla,

55! Malforngy: *i

resented Aug. 11, 1931 UNITED STATES PATENTE OFFICE WARNER T. TABB, O FMAHWAH, NEW JERSEY, ASSIGNOR T0 THE EISEMANN MAGNET() RPOBATION, OF NEWYORK, N. Y.. .A CORPORATION 0F NEW YORK SPEED'RESPONSIVE CONTROL;

Application :Bled J'uly 27,

This invention has to do with speed responsive devices. l Its underl ingthou ht is to utilize, as the source o energy or causing the performanceof the function that is to respond to a certain speed, the vibration ofan element which has a predetermined natural frequency and which is setin motion by the vibratory motion of another element whose frequencyvaries with the speed to which the device is to respond.

` The vibrator thus set in motion is caused to do work, by means of asuitable connec-V tion, either in controlling the supply of energy tothe machine whose speed it.

responds to, as in the case 'of a governor, or in operating someseparate instrumentality having a function which it is desired v torelate to a certain speed or range of speeds of the said machine.

It will be apparent that the device may be put to various uses. As anillustration, chosen because it is the best known and because theinvention was developed with reference particularl to this use, theinvention is. described hereln as used to govern the speed of themachine to whose speed it responds and, in particular, as it is used togovern the s eed of an internal combustion en'gine by utilizing thepulsations of the gas How through the intake line of the engine to setin motion a vibratory element connected to operate a throttle valve inthe said intake line. It is to be borne in mind however that theinvention in its broader aspects has many other fields of ap licationwhich are not to be deemed excluded by this description of the inventionas applied to the problem of governin I t is important to distinguish atthe outset, the form of the invention to be described here from theknown suction governor which depends upon the mean eective value of. thesuction for operating the controlling valve and upon the variation ofthis value with the speed of the engine. Such variation is not a veryclose function of the speed variation since it depends upon the load andupon other factors to a very material degree. The governing therebyeffected is not as accurate or as satisfactory gener- 1929. Serial No.381,631.

illustrated in the accompanying drawings and are described hereina terwith reference thereto.

In the drawings- Figure 1 is a view, partly in section, througha unitconsisting of a rotary valve, a vibrating element and a ratchet drivendifferential ear for translating the motion of the vibra-tlng elementinto a motion of the valve.

Figure 2 is a view in section on the line 2-2 of Figure 1 but with thevibrating element shown in elevation and withthe outer ratchet partlybroken away to show the planetary gear and the inner ratchet.

Figure 3 is a lview looking into the end cover at the right of Figures 1and 2 and showing the vibrating element in elevation.

Figure 4 is a plot of amplitude of the vibrating element against enginespeed showin a characteristic action of a goveernor o `the type shown inFigures 1, 2 and 3.

Figure 5- is a view, partly in section, of a similar governor unithaving aemodified form of device for operating the valve from thevibrating element.

Figure 6 is a sectional view of the same modified unit, the view beingtaken in a plane at right angles to that of Figure 5.

Figure 7 is a v1ew, partly in section, of a like unit with still anotherdevice for actuating the valve from the vibrating element.

'Figure 8 is a sectional view of the same unit in a plane at rightangles to that of Figure 7.

In the form of governor shown in Figures 1 and 2, the governor valve 10is mounted between the carburetor and the manifold in the intake line 11of an internal combustion engine which may be assumed to be of the fourcycle type in which each cylinder exerts a suction effort in the intakeonce for every two revolutions. The valve has a permissive movement of90 between open and closed positions, being turned by a spindle 30extending outside of the intake line and into the governor casing 12where it carries a ratchet actuated differential gear drive mechanismfor turning it in either direction. This mechanism consists of two bevelgears 13, 13', free to turn on the valve spindle and inmesh with aplanetary bevel gear 14. carried by a stud on a frame 15 that is mountedto turn bodily with the valve spindle. These gears have oppositelyacting ratchet wheels 16, 17 secure to them, by ,means of which the?7are turned as the ratchets are actuate by their respective awls 18, 19.The two lugs 34 spaced 90 ie in the path of the stud 35 and thus limitthe turning of the valve.

The vibrating element is mounted in a hemispherical casing 2O whichrests against the bell end 31 of the casing for the valve actuatingmechanism just described. This element 1s in two parts, each part beinga` semi-circular piece of thin resilient metal 21, 22 havin a weight 23,24fastened to it j on. each si e near the periphery. These 6 the wheelso as to ull on t semi-circular pieces may be integral or separate butin either case they are clamped 1n' the mid area of the element bydiametral members 32, but otherwise are free. The curved edge of eachsemi-circular disc just clears the wall of the casing which is formed asa true hemisphere in the region 33 of the. vibrating element in order toprovide a substantially constant clearance for all positions of thevibrating element. The diametral clamping members 32 are supported fromthe casing by webs 25 and are held together by bolts.

The pawl 18 for the ratchet 16 is connected to the weight 23 by a freepivotal joint, the end of the pawl engaging a pin extending across aslot in one of the weights 23, and the pawl 19 acting on the ratchet 17vis similarly .connected to the weight 24 the pawls being also supportedby their en"- gagement with the ratchet wheels. The Eawls are twopronged, one prong of each eing bent inwardly to engage between adjacentteeth of the ratchet wheel and to ush forward while the other prong isslotte and the slot 37 rests over the o posite side of lie teeth of thebackward stroke. n order to cause o site rotation of the ratchets, thepus ing prong of one pawl 18 engages its ratchet on the upper side andthe slotted pullin pawl 05 engages on the -under side, while lin t ecase vbias toward open is not necessar'.

ofthe other pawl 19, the pushing prong acts on the under side and thepulling awl on the upper, the teeth Aof the two ratc ets beingoppositely directed. (See Figure 2.) Thus oth pawls push on the ratchetswhen they swin toward them and pull on them when moving back, causingrotation of the two in opposite directions. The direction in which thevalve stem turns depends u on the net eiect of the two ratchets aecordmto the known principle of such diierentia gears, since both ratchets acton the planetary gear 14 through their respective bevel gears and whenone ratchet turns faster than the other it causes the planetary gear V14to roll on the bevel gear of the slower ratchet and hence to carry theframe 15 and spindle around with it.

The chamber in which the vibrating element is mounted is incommunication with the intake 11 on the engine side of the valve 10 byway of a passage 26 through the casing wall. By reason of this fact, thetwo vibrators making up the vibrating element are subjected to theinfluence of the pulsating gas, the frequency of whose vibrations orpulsations varies directly with the speed of the engine. There may be acoil spring 36 connected to the spindle and to the casing to stabilizethe valve and to give it a normal gosition but such a spri uch a springmay be use also to provi a means of adjusting the governing speed.

The two vibrators are so made that they have different natural periodsof vibration. The period being a function both of the resiliency of thethin disc and of the weight, this difference is easily brought about andstill is made capable of ready change byusin identical pieces ofresilient metal but with dierent movable weights on them. Further, thenatural periods of these weightspring combinations is of anorder ofmagnitude corresponding to a frequency about equal to the frequency ofthe gas pulsations caused by the engine speed that 1s the desiredmaximum.

As the frequency of gas pulsations increases and ap roaches the naturalfrequency of the v1 rators, it induces a vibratory motion thereof. Thevibrating part of lower natural fr uency is connected to the ratchetwhich ten" to open the valve while the other is connected to the valveclosing ratchet. When the speed is such that the vibrator of lowernatural frequency attains its naturalfrequence and hence its maximumamplitude the other vibrator is vibrating with a shorter amplitude as itis not at its natural frequency, and thus the net effect of the two isto urge the valve toward and to maintain it in its open osition. Ahigher speed, beyond that giving a pulsation frequency equal to that oft e natural Vfrequency of the part of lower natural frequency, theamplitude of the said part decreases while that of the other vibratorcontinues to increase as it approaches itsnatural frequency. It finallydominates and then the net effect of the whole vibrating element is toclose the Valve.

This action is illustrated in Figure 4 which is a plot of the variationof amplitude with variation of the frequency of gas pulsation or, inother words, with the engine speed. The amplitudes are of the twovibrators as induced by the gas pulsations, the upper curve A being thatof the vibrator of lower natural frequency while the inverted curve Brepresents the vibrator of higher natural freuency. The inversion is torepresent the di erent directions in which the two elements act, oneopening, the other closing the valve. The broken line curve C representsthe net effect of the two or the effect of the two vibrating elements asa whole. By changing the weights and the spring discs, the curves may bemade fiat or sharp as desired, a heavier weight with a correspondinglystiff spring giving a sharper turning for any given natural frequency.

It will be understood from known physical laws that in addition to thecurves shown,

a plot of the amplitudes over a greater rangeA of frequencies of theinducing vibrations would show other curves representing harmonies.These, however, are much weaker thanthe vibrations at the fundamental.The half tone of the opening part and the overtone of the closing part,of course, would give a desirable effect. properly designed element inwhich the strength 0f the springs is such as to revent vibration ofmaterial amplitude at tlie harmonic without preventing substantialvibration at the fundamental, the net effect of the two parts at theharmonic is negligible. Tt is even possible to make the differencebetween the natural frequencies of the two vibrators such that thehalf-tone 7 of the one of hi her frequency comes while the other one 1shavin a substantial amplitude at or near its fun amental and sufficientto overcome the half-tone.

In place of the pawl and rachet drive connection with a planetary gear,for operating the valve from the vibrating elementby converting thevibrato'ry` motion into cumulative motion in either direction, manyother mechanisms may be used, either electrical or mechanical. Asuitable mechanical modification is shown in Figures 5 and 6. Thevibrating element is in the form of a piston- (pring combination. Apiston 40 is mounte in a cylinder 41 and is of slightly smaller diameterthan the cylinder. The piston is held between two similar springs 42, 43put under initial compression and bearing against opposite sides of thepis- In any event, with a ton and opposite ends of the cylinder. Anotherspring 44 is attached to one side of the piston and rests at its otherend on a threaded plug 45 which passes through the cylinder wall andwhose threads have the same pitch as the turns of the spring so that itmay be moved into and out of the coil to limit the effective length ofthe latter.

There is also in this modification a different mechanism for translatingthe vibration of the piston into uni-directional rotary motion of thevalve spindle. This mechanism consists of a yoke 46 directly connectedto the piston and provided with a stem 47 at its other end sliding inabearing 48 in the casing. This yoke (mounted over the cam 49) which isfixed on the valve spindle 50 has bumpers 51, 52 preferably of hardfibre or some similar substance mounted at diagonally opposite cornersin position to engage the cam faces 53, 54 alternately. These faces areportions of a curve which may be the involute of the circle of the valvestem. They extend for 180 each, ending in radial faces 55, 56. A pin 57on the valve stem turns in a recess 58 which is a quarter segment of acircle and thus limits the movement of the spindle to 90.

Since there is but a one-part vibrating element and a uni-directionalmotion translating device, the valve in this modification must be urgedtoward open position by a coil spring 60 attached to the outer end ofthe valve stem and to the casing wall. The valve therefore normally isin open position. It is possible, of course, to apply the thought of thepreviously described modifications by providing two cams and twooppositely acting piston-bumper sets of different natural periods, oneacting to open the valve and the other to close it.

As the piston is given a vibration of substantial amplitude when thefrequency of gas pulsation in the inlet, communicated through thepassage 26, approaches the natural frequency of the piston-springdevice, the bumpers act on the cam faces 53, 54 and by their cumulativeeffect cause the valve stem to turn until the valve is closed. Theadjustable spring 44 permits the tuning or governing speed to be variedas its effect is to change the natural period of the vibrating element,of which this sprin is a part, corresponding to the weighted resilientdiscs in the other form described above.

As still another variation illustrating the many possibilities thatthere are of varying the particular construction of the elements of thisinvention, there is shown values, the result being two vibrators ofdifferent natural eriod of vibration. The discs are clampe on adiametral web 74 by a bar 75 held thereto by bolts 76. The vibratorymotion is translated into rotary motion by a neumatic motor made u of acylinder 77) with a piston 78 sli able. therein and check'valves 79, 8Oopening respectively from the diaphra m chambers 81, 82 to oppositesides of: the piston. A partition 83 integral with the web 74 forms thevalve head and separates the diaphra m chambers from the interior of thecylin er 77. A passage 84 leads from the discharge side of the valve tothe outer end of the cylinder while the valve 79 opens directly to thecylinder, thus giving separate .outlets from the two dia liragm chambersto opposite sides of the piston 78. The piston is connected to the valvestem by a rod 85, extending through the web 74 and by a crank 86 andconnecting rod 87. There is a stabilizing spring 88 on the end of thevalve stein tendin to hold the valve open and to hold the piston at theright hand end of the cylinder, but it isnot necessary with the two-partdouble acting vibrating element. A in 89 and quarter circle recess 90limit the permissive turnin of the valve.

As t e two parts of the diaphragm are set in motion by the pulsations ofthe gas in the suction inlet as communicated to the diaphragm chambers81, 82 by the assage 26, the vibrators discharge the gas t rough thevalves 79, 8O and thus build up pressure on opposite sides of thepiston. The vibrator 70, 72 of lower natural frequenc causes the gas tobe delivered past the va ve 79 from the chamber 81 to the left hand sideof the cylinder while the other vibrator delivers gas past the valve 8Oto the channel 84 which leads to the other side of the piston.

As in the case of the form shown in Figures 1, 2 and 3, the vibrator oflower nat ural frequency exerts an effort tending to hold the valve openand dominates until the frequency of pulsation exceeds its naturalfrequency, whereu on its amplitude decreases and that o the othervibrator increases since the latter is being brought to its naturalfrequency. A point is reached at which the latter vibrator dominates byreason of eater amplitude and greater pumpinge ort and the result is amovement of the cpiston 78 to the left, turning the valve towar closedposition. As the speed decreases upon t rottling, the effect of thishigher frequency vibrator decreases and the valve 1s again openedAeither part way or wholly. The governing continues in this.``

vwa lt will be evident that the type of-vibrating element may be variedand that different expedients may be adopted to convert its vibratorymotion into a cumulative motion suitable for a valve. There may be atwopart vibrating element acting to open the valve over one range ofpulsation frequencies and to close it at another, or there ma be asingle vibrator with an opposing orce' such as that of a spring. For theelement that induces the motion of the vibrators of e electricalsystems, all of which involve4 some vibration or pulsation that variesin frequency with the speed of the engine and therefore may supply theenergy and periodic eiect which induces andmaintains the motion of thevibrators.

The motion of the vibrating element may 4be utilized in various ways toact on the valve or other device-directly or to act on a pilot or relaymechanism as is a common thing in other controllers of valves, switchesand the like.

The mechanisms described here are illustrative of the underlyinprinciple and of simple, effective ways o putting it to use. It will beappreciated that there are many other forms, some of whichI involvecomplications such as phase diifeiences between the maximum or minimumeffort of the iny.

ducing medium and the position of the induced vibrator in its path. Insome cases these phase differences may be utilized and in others theymayl be com ensated for. Such forms present elds for t e application ofordinary skill or of further inventive effort within the scope of thebroad invention here disclosed. I wish to include therefor within thescope of protection 'ven by a patent all suchmethods and mec amsms ascome within claims.-

I claimy o 1. A speed responsive device comp A a vibrating elementhaving a predetermm natural period of vibration, means for sub- ]'ectnsaid element to the influence of .pulsating with a frequency v a ingwith the speed under concern to in uee sympatheticv vibration of saidelement, and means for utilizing the motion and energy of saidelementwhen vibrating at and near its natural' eriod to cause theperfomance lof the spee responsive function.

'2. A speed responsive device comprisii'g a vibrating element having apredetermin natural period of vibration means for subjecting saidelement to a vibration inducing miluence having a frequency of vibrationthe .fair range of the following for subjecting said element to avibrationv inducing influence having a frequency of vibration varyinwiththe speed under concern, and means or utilizing the motion andenergy of said element whenvibrating at and near its natural period tocause the speed responsive function to be performed.

4. In combination with 'a prime mover,

means for controlling the supply. of energyA thereto, a vibratoryelement havin a redetermined natural period of vibration, means forsubjecting said element to the inluence of pulsations Whose frequencyvaries with the s ed of the prime mover to induce sympathetic vibrationof said element, and means actuated by said element when vibrating foroperating said controlling means.

5. The method of performing a function, in response to a part of thespeed range of a mechanism, which comprises settin a primary medium invibration with a requency varying with the speed of the said 80mechanism, causing said medium to induce vibratory motion of an elementhavin a natural period of vibration within t at' range of frequencies ofsaid (primary element which corresponds to sai part of the speed range,and utilizing the motion and energy of Ysaid element when vibrating tocause the performance of the speed responsive function.

6. In a speed responsive governor, a valve and valve closing mechanism,a chamber with a vibrating'element therein having a predeterminednatural period of vibration, provision for utilizing the energy of saidelement when vibrating to operate said valve closin mechanism and meansfor subjecting said e ement to a vibration inducing influence having aperiod of vibration varying with the speed controlled by said valve.

7. In a speed responsive governor,a valve, a vibrating element having apredetermined period of vibration, means for subjecting said element toa vibration inducing influence of varying frequency, and provision forconverting the vibratory motion of said ,element into cumulative motioneffective to operate said valve. A

8. In a speed responsive overnor, a valve casing, a valve therein anvalve operating means, a chamber and a vibrating element therein havinga predetermined natural eriod of vibration, together with an inlet romthe valve casing to said chamber and provision for utilizing the "energyof said element when vibrating to operate the valve operating means.

9. In a speed responsive device, a vibrating element comprisin aweighted spring, means for subjecting said element to a vibrationinducing influence having a frequency varying with the speed underconcern, and means for utilizing the ener y of said element whenvibrating to perfgorm the speed responsive function.

10. In a speed responsive device, a vibrat-v ing element comprising apiece of resilient sheet metal and a weight carried thereby, means forsubjecting said element to a vibration inducing influence having afrequency of vibration varying with the speed under concern, and meansutiliz-ing the energy of said vibrating element to perform the speedresponsive function.

11. In a speed responsive device, a chamber having a wall portionconforming to a part of a sphere, a semi-circular piece of resilientmetal mounted to vibrate with its curved edge free and close to saidwall portion, aweight carried by said piece, means for subjecting saidpiece to a vibration inducing influence of varying period of vibration,and provision for utilizing the energy of said weighted metal piece whenvibrating to cause the' performance of the speed responsive function.

12. In a speed responsive device, two vibrating elements of differentnatural periods of vibration, mechanism for performing the functionresponding to the speed under concern, means for utilizing the energy ofone element when vibrating to actuate said mechanism and for utilizingthe energy of the other element when vibrating to restrain theperformance Aof said function, the two elements being subjected to avibration inducing influence having a frequenc of vibration varying withthe speed un er concern.

13. In combination with a prime mover, a control for the supply ofenergy thereto, two vibrating elements of different natural periods ofvibration subjected to a vibration inducing influence having a frequencyof vibration varying with the s eed of the prime mover, means utilizingt e vibration of the element of higher natural period to cause saidcontrol to stop the supply of energy and means utilizing the vibrationof elementA of lower natural period to cause the control to permit thesupply of energy.

14. In a speed responsive overnor, a valve, a chamber with two vi ratingelements therein of different predetermined natural periods ofvibration, means utilizin the energy of the element of higher naturaperiodl to close the valve and means utilizing the energy of the otherelement to open the velement tuned to vibrate at a pre 15. A speedcontrol device comprising eterm frequency, means for directly subjectingsaid element to the inliuence of a gas tplulsatin with a frequencyvarying with e spee to cause sald element to vibrate when its lpulsations correspond to the frequency of said element, s eedcontrolling means and means for utilizing the motion and energy of saidelement when vibrating to cause the operation of speed controllingmeans.

16.' A speed control device com rising an element tuned to vibrate at apre etermmed fre uency, means to subject said element to a v1 rationinducing influence having a frequency of vibrations varying with thespeed to be controlled2 said influence being effective to cause saldelement to vibrate when its frequency of vibration corresponds to thevibration frequency of said element and ineffective at other frequenciesof vibration, speed controlling means and means for using the motion andenergy of said ele ment when vibrating to control the operation of saideed controlling means.

17. A spee control device com rising an element tuned to vibrate at apre etermlned fre uency, means to subject said element to a v1 rationinducing influence having a frequency of vibration varyin with the speedto be controlled to cause said element to vibrate when its frequency ofvibration corresponds to the frequency of vibration of the element,speed controlling means and means for utilizing the motion d ener ofsaid element when vibratin t cause t e operation of said speed contromeans.

18. In a speed responsive overnor a valve, a vibrating element tune to api'edetermined frequency, means for subjecting said element to avibration inducin influence of varying frequency, said vi rationinducing iniiuence being effective to vibrate said element when itsfrequency of vibration corresponds to the vibration frequency of saidelement and ineffective at other frequencies of vibration, and provisionfor converting the vibratory motion of said element into cumulativemotion eective to operate said valve.

In testimony whereof I have signed my name to this specification.

' WARNER T. TABB.

anmed4

